Evaluation of Structural Treatment Efficacy against Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae) Using Meta-Analysis of Multiple Studies Conducted in Food Facilities

Comparison of different traps and attractants in 3 food processing facilities in Greece on the capture of stored product insects

Certain lures are marketed toward particular pests or classes of pests, while others might be multi-species lures. Investigative aims for this study included both which trap was most sensitive and whether different combinations of traps and attractants were delivering novel information about the stored product insect community. Comparisons were made for all combinations of 3 commercial traps and 4 different attractants plus an untreated control on the capture of stored-product insects for 2 consecutive years in 3 food processing facilities in Central Greece. The traps used in the experiments were Dome Trap (Trécé Inc., USA), Wall Trap (Trécé) and Box Trap (Insects Limited, Ltd., USA). The attractants that were evaluated were 0.13 g of (i) PantryPatrol gel (Insects Limited), (ii) Storgard kairomone food attractant oil (Trécé), (iii) wheat germ (Honeyville, USA), and (iv) Dermestid tablet attractant (Insects Limited). The traps were inspected approximately every 15 days and rotated. A total of 34,000+ individuals were captured belonging to 26 families and at least 48 species. The results indicated that Indian meal moth, Plodia interpunctella (Hübner), red flour beetle, Tribolium castaneum (Herbst), and cigarette beetle, Lasioderma serricorne (F.) were the most abundant. Although there were noticeable differences among the different traps and attractants for specific species, all combinations provided similar information on population dynamics. Generally, Dome traps baited with either the oil or the gel, were found to be the most sensitive. The results of the present study demonstrate the importance of long-term trapping protocols, as a keystone in IPM-based control strategies in food processing facilities.

Estimating long-term spatial distribution of Plodia interpunctella in various food facilities at Rajshahi Municipality, Bangladesh, through pheromone-baited traps

The Indian meal moth, Plodia interpunctella (Hübner), feeds on a wide range of commodities in most regions of the world. The present study presents six years of monitoring data for P. interpunctella in pheromone-baited traps by analyzing the trends of spatial variability, in five food facilities located in the Rajshahi municipality area of Bangladesh. We also tracked insect incidence at different spatial scales and evaluated the impact of food facility types and storage structures on insect populations. Our model showed an aggregated distribution pattern for P. interpunctella. Population patterns of P. interpunctella varied significantly among facilities. The highest number of moths captured was recorded in a grain retailer located at Municipal market, followed by a grain warehouse at Harian, pulse mill at Kazla, flour mill at Sapura and grocery shop at Katakhali. The population fluctuation of P. interpunctella moths was similar among the different locations tested, while there were no captures during the winter period. Our results indicate that long-term monitoring in a wide range of areas can be used to indicate population outbursts, under an area-wide management strategy.

Tribolium castaneum: A Model Insect for Fundamental and Applied Research

Tribolium castaneum has a long history as a model species in many distinct subject areas, but improved connections among the genetics, genomics, behavioral, ecological, and pest management fields are needed to fully realize this species' potential as a model. Tribolium castaneum was the first beetle whose genome was sequenced, and a new genome assembly and enhanced annotation, combined with readily available genomic research tools, have facilitated its increased use in a wide range of functional genomics research. Research into T. castaneum's sensory systems, response to pheromones and kairomones, and patterns of movement and landscape utilization has improved our understanding of behavioral and ecological processes. Tribolium castaneum has also been a model in the development of pest monitoring and management tactics, including evaluation of insecticide resistance mechanisms. Application of functional genomics approaches to behavioral, ecological, and pest management research is in its infancy but offers a powerful tool that can link mechanism with function and facilitate exploitation of these relationships to better manage this important food pest.

Synthetic and Natural Insecticides: Gas, Liquid, Gel and Solid Formulations for Stored-Product and Food-Industry Pest Control

The selective application of insecticides is one of the cornerstones of integrated pest management (IPM) and management strategies for pest resistance to insecticides. The present work provides a comprehensive overview of the traditional and new methods for the application of gas, liquid, gel, and solid physical insecticide formulations to control stored-product and food industry urban pests from the taxa Acarina, Blattodea, Coleoptera, Diptera, Hymenoptera, Lepidoptera, Psocoptera, and Zygentoma. Various definitions and concepts historically and currently used for various pesticide application formulations and methods are also described. This review demonstrates that new technological advances have sparked renewed research interest in the optimization of conventional methods such as insecticide aerosols, sprays, fumigants, and inert gases. Insect growth regulators/disruptors (IGRs/IGDs) are increasingly employed in baits, aerosols, residual treatments, and as spray-residual protectants for long-term stored-grain protection. Insecticide-impregnated hypoxic multilayer bags have been proven to be one of the most promising low-cost and safe methods for hermetic grain storage in developing countries. Insecticide-impregnated netting and food baits were originally developed for the control of urban/medical pests and have been recognized as an innovative technology for the protection of stored commodities. New biodegradable acaricide gel coatings and nets have been suggested for the protection of ham meat. Tablets and satchels represent a new approach for the application of botanicals. Many emerging technologies can be found in the form of impregnated protective packaging (insect growth regulators/disruptors (IGRs/IGDs), natural repellents), pheromone-based attracticides, electrostatic dust or sprays, nanoparticles, edible artificial sweeteners, hydrogels, inert baits with synthetic attractants, biodegradable encapsulations of active ingredients, and cyanogenic protective grain coatings. Smart pest control technologies based on RNA-based gene silencing compounds incorporated into food baits stand at the forefront of current strategic research. Inert gases and dust (diatomaceous earth) are positive examples of alternatives to synthetic pesticide products, for which methods of application and their integration with other methods have been proposed and implemented in practice. Although many promising laboratory studies have been conducted on the biological activity of natural botanical insecticides, published studies demonstrating their effective industrial field usage in grain stores and food production facilities are scarce. This review shows that the current problems associated with the application of some natural botanical insecticides (e.g., sorption, stability, field efficacy, and smell) to some extent echo problems that were frequently encountered and addressed almost 100 years ago during the transition from ancient to modern classical chemical pest control methods.

Control Failures Following Insecticide Applications in Commercial Agriculture: How Often Do They Occur? A Case Study of Lygus hesperus (Hemiptera: Miridae) Control in Cotton

Although surveys of pest populations documenting evolved insecticide resistance often suggest abundant potential for insecticide control failures, studies documenting the actual occurrence of such failures in commercial agriculture are rare. If farmers currently practice adaptive management, abandoning the use of insecticides once resistance emerges, actual control failures could be rare. Here I use data gathered by independent pest management consultants to describe a case study of the realized efficacy of commercial field applications of insecticides, examining the control of Lygus hesperus Knight on cotton. On average, insecticides reduced target pest populations to 19% of their preapplication densities. Short-term efficacy of insecticides was variable, but only one severe control failure was observed (1 of 50, 2%). The rarity of severe control failures observed in this study is in agreement with the few other studies conducted in commercial settings, but additional research is needed to assess the generality of this result. Although pesticides can cause longer-term problems, including target pest resurgences and secondary pest outbreaks, risk-averse attitudes among farmers coupled with relatively consistent short-term insecticide efficacy may be potent forces propelling farmers toward the use of insecticides.

Residual Efficacy of a Deltamethrin Emulsifiable Concentrate Formulation against Rhyzopertha dominica (F.) and Sitotroga cerealella (Oliver) after Partial Treatment of Brown Rice

Rhyzopertha dominica (Fab.), the lesser grain borer, and Sitotroga cerealella (Olivier), the Angoumois grain moth, are internally feeding stored product insects that can infest raw grains. In this test, brown rice was treated with 0.5 and 1.0 ppm of a new emulsifiable concentrate (EC) formulation of the pyrethroid deltamethrin and stored for 12 months. One day after treatment, and every 3 months for 12 months, treated rice was mixed with untreated brown rice in the following ratios: 0:100 (untreated controls), 10:90, 25:75, 50:50, 75:25, and 100:0 (all treated). Bioassays were conducted by exposing 10 parental adults of each species on the rice mixtures and assessing progeny production, feeding damage, and weight loss. The progeny of S. cerealella ranged from 105.6 F₁ adults on untreated brown rice to 69.4 F₁ adults on 100% treated rice, but there was little feeding damage or weight loss. The progeny production of R. dominica declined from 177.4 F₁ adults on untreated rice to 9.8 F₁ adults on 100% treated rice. Weight loss and feeding damage were correlated with progeny production. The results show that the new deltamethrin formulation could be used for protection of brown rice, but S. cerealella may be less susceptible to deltamethrin compared to R. dominica.

An Ecoinformatics Approach to Field-Scale Evaluation of Insecticide Effects in California Citrus: Are Citrus Thrips and Citrus Red Mite Induced Pests?

Experimental approaches to studying the consequences of pesticide use, including impacts on beneficial insects, are vital; however, they can be limited in scale and realism. We show that an ecoinformatics approach that leverages existing data on pesticides, pests, and beneficials across multiple fields can provide complementary insights. We do this using a multi-year dataset (2002-2013) on pesticide applications and density estimates of two pests, citrus thrips (Scirtothrips citri (Moulton [Thysanoptera: Thripidae])) and citrus red mites (Panonychus citri McGregor [Acari: Tetranychidae]), and a natural enemy (Euseius spp. predatory mites) collected from citrus groves in the San Joaquin Valley of California. Using correlative analyses, we investigated the long-term consequences of pesticide use on S. citri and P. citri population densities to evaluate the hypothesis that the pest status of these species is largely due to the disruption of natural biological control-i.e., these are induced pests. We also evaluated short-term pesticide efficacy (suppression of citrus thrips and citrus red mite populations immediately post-application) and asked if it was correlated with the suppression of Euseius predator populations. Although the short-term efficacy of different pesticides varied significantly, our dataset does not suggest that the use of citrus pesticides suppressed Euseius densities or worsened pest problems. We also find that there is no general trade-off between pesticide efficacy and pesticide risk to Eusieus, such that highly effective and minimally disruptive compounds were available to citrus growers during the studied time period.

Effects of High Temperatures on the Mortality of Stegobium paniceum (L.) (Coleoptera: Anobiidae)

As an alternative to chemical fumigants, heat treatment has been a widely used physical method to successfully control stored-product insects in empty grain storage and food processing facilities. The drugstore beetle, Stegobium paniceum (L.) (Coleoptera: Anobiidae) is one of the most destructive stored-product insects in the world. The mortality of the eggs, larvae, pupae, and adults of S. paniceum was investigated when exposed to 43, 47, 51, and 55°C for different time intervals. The mortality rate of the S. paniceum eggs, larvae, pupae, and adults was found to significantly increase with increased exposure time and temperature, and the pupae were the most heat-tolerant stage. The mortality rate of the S. paniceum pupae was <43.3%, while the mortality rate of the S. paniceum eggs, larvae, and adults achieved nearly 100.0% when they were exposed to 43, 47, 51, and 55°C for 6 h, 17.5 min, 120 s, and 30 s, respectively. The current results favor designing a heat treatment protocol to successfully disinfest S. paniceum in practice.

Effect of the Presence of Live or Dead Insects on Subsequent Captures of Six Stored-Product Beetle Species: The Relative Species Matters

In trapping programs prior capture of individuals of the same or different species may influence subsequent attractiveness of the trap. To evaluate this process with stored-product insects, the effect of the presence of dead or alive adults in traps on the behavioral responses of six stored-product insect species, Tribolium confusum Jacquelin du Val, T. castaneum (Herbst) (Coleoptera: Tenebrionidae), Sitophilus oryzae (L.), S. granarius (L.) (Coleoptera: Curculionidae), Oryzaephilus surinamensis (L.) and O. mercator (Fauvel) (Coleoptera: Silvanidae), was studied in choice tests under laboratory conditions. Two series of tests were carried out. In the first series, the choice was between either alive or dead adults of same species and blank (no adults). Overall, dead adults had the strongest influence, increasing the response of S. oryzae, S. granarius, O. surinamensis, and O. mercator and decreasing the response of the two Tribolium species. Presence of alive adults generally did not result in a response different from blank, except for T. castaneum and O. surinamensis that had a reduced response. In the second series of tests, the choice was between alive or dead individuals of the species vs. alive or dead individuals of its relative cogeneric species. For choices between alive individuals, S. oryzae, S. granarius, and O. surinamensis showed a preference for alive individuals of the same species vs. the cogeneric species, and for all the other species there was no preference. For choices between dead individuals, T. castaneum exhibited a preference for individuals of the same species, while S. oryzae, S. granarius, and O. mercator showed a preference for individuals of the cogeneric species, and all other combinations did exhibit a preference. Our results suggest that traps containing alive and dead individuals of the same and other species can seriously affect the response and capture of additional insects.

Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis

The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the respective costs.